[Bug 1589526] Re: fcp multipath devices does not exist after reboot

[Dimitri John Ledkov]

Are you trying to (a) install ubuntu onto multipath device as root file
system or (b) post-install, add and activate a multipath zhcp device for
arbitrary data storage?

Reading the installer logs, I see following observations.

The installation was not performed onto a multipath device.

It is recommended to use the installer, and install onto multipath
device directly, if that is desired. The installation was performed onto
a ECKD dasd drive 0192.

Typically, one is presented with the zhcp screen to activate zhcp
devices, and then choose an assembled multipath device, at install time.
Then it is correctly setup, in fstab, in the initramfs, in zipl.conf and
the generated bootmap with zipl.

See following:
May 11 05:54:40 kernel: [  153.539344] dasd-eckd 0.0.0192: A channel path to the device has become operational
May 11 05:54:40 kernel: [  153.541193] dasd-eckd 0.0.0192: New DASD 3390/0C (CU 3990/01) with 2885 cylinders, 15 heads, 224 sectors
May 11 05:54:40 kernel: [  153.554997] dasd-eckd 0.0.0192: DASD with 4 KB/block, 2077200 KB total size, 48 KB/track, compatible disk layout
May 11 05:54:40 kernel: [  153.561502]  dasda:VOL1/  0X0192: dasda1 dasda2 dasda3
May 11 05:54:43 s390-dasd[5459]: Printing hashmark every 10 cylinders.
May 11 05:54:43 s390-dasd[5459]: 
May 11 05:55:08 kernel: [  180.968672] dasd-eckd 0.0.0192: DASD with 4 KB/block, 2077200 KB total size, 48 KB/track, compatible disk layout
May 11 05:55:08 kernel: [  180.968678] dasda: detected capacity change from 0 to 2127052800
May 11 05:55:09 s390-dasd[5459]: 
May 11 05:55:09 s390-dasd[5459]: 
May 11 05:55:09 s390-dasd[5459]: Finished formatting the device.
May 11 05:55:09 s390-dasd[5459]: Rereading the partition table... ok
May 11 05:55:09 kernel: [  180.969253]  dasda:
May 11 05:55:09 kernel: [  182.258534]  dasda:VOL1/  LX0192:
May 11 05:55:30 main-menu[361]: INFO: Menu item 's390-zfcp' selected
May 11 05:55:30 net/hw-detect.hotplug: Detected hotpluggable network interface enc900
May 11 05:55:30 net/hw-detect.hotplug: Detected hotpluggable network interface lo
May 11 05:55:30 s390-zfcp[5490]: DEBUG: DETECT: The zfcp device driver is not loaded
May 11 05:55:30 s390-zfcp[5490]: WARNING **: Could not open directory: /sys/bus/ccw/drivers/zfcp/: No such file or directory
May 11 05:55:31 main-menu[361]: INFO: Menu item 'disk-detect' selected
May 11 05:55:31 anna-install: Installing mmc-modules
May 11 05:55:31 disk-detect: insmod /lib/modules/4.4.0-21-generic/kernel/drivers/scsi/device_handler/scsi_dh_rdac.ko 
May 11 05:55:31 kernel: [  203.950555] rdac: device handler registered
May 11 05:55:31 kernel: [  203.953114] alua: device handler registered
May 11 05:55:31 disk-detect: insmod /lib/modules/4.4.0-21-generic/kernel/drivers/scsi/device_handler/scsi_dh_alua.ko 
May 11 05:55:31 disk-detect: insmod /lib/modules/4.4.0-21-generic/kernel/drivers/scsi/device_handler/scsi_dh_hp_sw.ko 
May 11 05:55:31 disk-detect: insmod /lib/modules/4.4.0-21-generic/kernel/drivers/scsi/device_handler/scsi_dh_emc.ko 
May 11 05:55:31 kernel: [  203.955593] hp_sw: device handler registered
May 11 05:55:31 kernel: [  203.958012] emc: device handler registered

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https://bugs.launchpad.net/bugs/1589526

Title:
  fcp multipath devices does not exist after reboot

Status in debian-installer package in Ubuntu:
  New

Bug description:
  == Comment: #0 - Ofer Baruch <OFERBA at il.ibm.com> - 2016-06-06 06:37:19 ==
  Hi,

  i have installed an Ubuntu Server from the installation ISO.
  i then installed multipath support (multipath-tools and multipath-tools-boot).
  i added an FCP device, format it, mount it and added to the fstab using it's /dev/mapper representation. everything worked fine...
  i then reboot the server and it failed to start due to the missing /dev/mapper device that needs to be mounted (as the fstab states).
  i get into maintenance mode.

  i am not using cio_ignore and the devices are available in maintenance mode.
  running multipath -ll will fail to show the device (as expected... that is why the boot failed).
  running multipat without any parameters (to rescan) will find the devices and it will now show on multipath -ll.

  i was able to get around this by rebuilding the initrd and running
  zipl... but that should not be the case. multipath should scan during
  reboot to find all the devices available.

  i am attaching both an sosreport and dbginfo for you to review.
  i hope this is something i am doing wrong but i don't think so...
  either way i would love to get a quick workaround that will avoid this issue without rebuilding the initrd.

  == Comment: #4 - Hendrik Brueckner <brueckner at de.ibm.com> - 2016-06-06 06:44:53 ==
  Hi Ofer,

  (In reply to comment #0)
  > i have installed an Ubuntu Server from the installation ISO.
  > i then installed multipath support (multipath-tools and
  > multipath-tools-boot).
  > i added an FCP device, format it, mount it and added to the fstab using it's

  How did you add the FCP device?

  == Comment: #5 - Ofer Baruch <OFERBA at il.ibm.com> - 2016-06-06 07:07:42 ==
  using: 

  chzdev zfcp-host <fcp_vdev> -e -p

  that is after i vary the device online.
  as i said the device comes online just fine... i can see all the /dev/sd* devices.
  i am just missing the multipath device.

  == Comment: #6 - Ofer Baruch <OFERBA at il.ibm.com> - 2016-06-06 07:11:09 ==
  the missing file is:
  /dev/mapper/3600507630bffc0470000000000002333

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